Petri dish

ABSTRACT

A CONTAINER FOR THE CULTURING OF MICRO-ORGANISMS COMPRISES A TRANSPARENT COVER MEMBER WHICH INCLUDES A SUB STANTIALLY FLAT TOP PORTION WHICH MERGES INTO A CONTINUOUS DEPENDING SIDE WALL, AND A TRANSPARENT BODY MEMBER HAVING A SUBSTANTIALLY FLAT BOTTOM PORTION MERGING INTO AN UPSTANDING CYLINDRICAL WALL PORTION WHICH CARRIES ON ITS OUTER SURFACE AN OUTWARDLY EXTENDING PERIPHERAL FLANGE PROVIDED WITH A PLURALITY OF INWARDLY EXTENDING SLOTS, SAID FLANGE BEING SPACED UPWARD FROM THE BOTTOM PORTION AND AWAY FROM THE LOWER EDGE OF SAID COVER SIDE WALL, THE OUTER EDGE OF SAID FLANGE EXTENDING BEYOND THE EXTERIOR OF SAID COVER SIDE WALL TO PERMIT GRASPING OF THE FLANGE BY THE FINGERS.

March 14, 1972 N. L. BUTERBAUGH 3,649,463

PETRI DISH Filed Oct. 10,1969

FIG. 4

INVENTOR 3 NOEL L. BUTERBAUGH ATTORNEY United States Patent Olfice 3,649,463 PETRI DISH Noel L. Buterbaugh, Bethesda, Md., assignor to Microbiological Associates, Inc., Bethesda, Md.

Filed Oct. 10, 1969, Ser. No. 865,292

Int. Cl. C12k N US. Cl. 195139 9 Claims ABSTRACT OF THE DISCLOSURE A container for the culturing of micro-organisms comprises a transparent cover member which includes a substantially flat top portion which merges into a continuous depending side wall, and a transparent body member having a substantially flat bottom portion merging into BACKGROUND OF THE INVENTION Containers of the type commonly known as Petri dishes, for the cluture of micro-organisms, have long been employed for the growth of bacteria, molds, and the like on sterile solid culture media. Petri dishes usually comprise a dish or body member having a flat bottom and a cylindrical upstanding wall, and a cover member having a fiat top with a downwardly depending side wall which fits over and surrounds the outside of the wall of the dish portion. Petri dishes are usually transparent, and may be made of glass or of molded plastic material. The cover wall usually extends downward close to the bottom of the dish.

One of the major drawbacks of this conventional construction has been that, in order to lift the Petri dish, the user will customarily extend his fingers under the edge of the cover member and grasp the bottom edge of the body member. Since the fit is loose, the dish portion containing the culture may slip from the fingers, leaving the user holding only the cover, thus exposing the contents of the dish to contamination and loss. Another alternative for picking up the conventional Petri dish is to slide the entire dish off the edge of the surface on which it rests, but this is not feasible where the dish rests in a recess in a supporting tray.

GENERAL DESCRIPTION OF THE INVENTION In accordance with the present invention there is provided a novel contained for microorganism culture, and which is an improved Petri dish.

A principal object of the invention is to provide a Petri dish which includes means for lifting the dish and cover without disturbing the cover. Still another object is to provide a transparent Petri dish having an integrally molded plastic cover member and culture dish member whereby contamination of the respective members by each other is minimized.

These and other objects will become apparent as the description proceeds in the following part of the specification wherein the details of construction of a presently preferred embodiment are set forth, together with the accompanying drawings.

While the principles of the invention will be described with particular reference to their embodiment in a Petri 3,649,463 Patented Mar. 14, 1972 dish, it will be understood that such description is for purposes of illustration only, and that these principles are capable of adaptation to a variety of containers having the same general configuration and structure.

DESCRIPTION OF THE PREFERRED EMBODIMENT The novel features and operation of the Petri dish of the present invention will be better understood by reference to the accompanying drawings, in which:

FIG. 1 is a view in perspective of the container cover and body member separated from each other;

FIG. 2 is a plan view of the body or dish member showing the peripheral flange and slots therein;

FIG. 3 is a cross-section of the dish member in association with the cover member; and

FIG. 4 is a plan view of the body or dish member showing the peripheral flange without the slots.

Referring now to the drawings, FIG. 1 shows the Petri dish type container of the invention, which may be of any desired cross-sectional form, but in the embodiment shown is cylindrical in cross-section. The container comprises a body or dish member 10, and a cover member 20 adapted to fit over and surround the outside of the wall of the body member. The cover member 20 includes a substantially flat portion 21 which merges into a continuous depending side wall 22 having a lower edge 23.

The body member 10 has a bottom portion 11 which is substantially fiat, and which merges into an upstanding wall portion '12 which is substantially cylindrical and which is advantageously integral with said bottom portion. The body member 10 is provided with a peripheral flange 13 attached thereto, which extends outwardly from the exterior of the wall 12 and which serves as a means of gripping the body member 10 in order to lift it and its contents, whether or not the cover member 20 is in place. Preferably the flange is integral with the wall portion.

In a preferred embodiment of the invention, there extends inwardly from the outer edge of the peripheral flange 13 a plurality of slots 14, which may be of any desired configuration, but are rectangular in the embodiment shown in FIGS. 1 and 2, and which extend inwardly from, and are spaced equidistantly around, the flange edge. These slots 14 serve to permit drainage from the flange of any liquid which may accumulate thereon in case of spillage, thus minimizing contamination. Preferably there are 4 slots equally spaced around the flange.

The peripheral flange 13 is positioned so as to be spaced away from the bottom of the dish a suitable distance to permit ready grasping of the flange edge by the fingers, but at the same time it is located at a distance from the top edge 15 of the wall 12 sufficient to prevent contact between the upper surface of the flange and the lower edge 23 of the cover side wall when the cover is in place. It is a special feature of the invention that the lower edge 23 of the cover wall does not come into contact with nor rest upon the flange surface. This serves to prevent the cover edge from being contaminated by the flange. In the embodiment shown in the drawings, the flange is positioned about two-thirds of the distance from the upper edge 15 of the dish wall, and about one-third of the distance from the bottom edge.

Both the cover and the container body may be made of a transparent plastic material, such as, for example, polystyrene, polymerized methyl styrene, methyl methacrylate, polypropylene and the like, for light weight and resistance to breakage, and to sterilizing temperatures.

In use, there is introduced into the dish member a culture medium which may either be of a semi-rigid consistency, such as gelatin or agar, and which is inoculated with the organism to be grown, or which may be a liquid medium, such as is used for the growth of cell cultures and tissue explants, and in which the risk of spillage is present; the cover is then applied to the dish. When it is desired to transfer the Petri dish or to lift it for inspection, the edge of the flange is grasped with the fingers, the cover remaining in place undisturbed.

What is claimed is:

1. A transparent container for the culturing of micro organisms comprising:

(a) a cover member including a substantially flat top portion which merges into a continuous depending side wall;

(b) a body or dish member having a substantially flat bottom portion merging into an upstanding Wall portion adapted to receive and support said cover member; and

(c) a peripheral flange attached to and extending outwardly around the exterior of said body member wall, the outer edge of said flange extending beyond the exterior of wall of said cover member when the cover is applied to the body member, said flange being positioned at a distance above the bottom edge of the body member sufficient to permit grasping thereof and at a distance below the top edge of the body wall sufiicient to prevent contact between the upper surface of the flange and the lower edge of the cover wall.

2. A transparent container for the culturing of microorganisms comprising:

(a) a cover member including a substantially flat top portion which merges into a continuous depending side wall;

(b) a body or dish member having a substantially flat bottom portion merging into an upstanding wall por- 4 tion adapted to receive and support said cover member; and (c) a peripheral flange attached to and extending outwardly around the exterior of said body member wall, the outer edge of said flange extending beyond the exterior of wall of said cover member when the cover is applied to the body member, said flange being positioned at a distance above the bottom edge of the body member sufficient to permit grasping thereof and at a distance below the top edge of the body wall suflicient to prevent contact between the upper surface of the flange and the lower edge of the cover wall, said flange including a plurality of slots extending inwardly from, and spaced equidistantly around the peripheral edge thereof. 3. The container of claim 1 which is a Petri dish. 4. The container of claim 1 in which the flange is integral with the body member wall.

5. The container of claim 1 which is made of transparent plastic.

6. The container of claim 2 in which said slots are substantially rectangular in shape.

7. The container of claim 2 which is a Petri dish. 8. The container of claim 2 in which the flange is integral with the body member wall.

9. The container of claim 2 which is made of transparent plastic.

References Cited UNITED STATES PATENTS ALVIN E. TANENHOLTZ, Primary Examiner 

